Portuguese police had detailed images of two suspects in the Madeleine McCann case but would not release them.

The e-fits have been finally published 15 months after the three-year-old vanished from her family's apartment in Praia da Luz last May.

The pictures could have played a vital part in helping to eliminate suspects or stop any abductor from fleeing the country with Madeleine.

In the UK, pictures of suspects are released nationwide and printed in as many outlets as possible to help police track wanted people down as soon as possible in the days after a child goes missing.

However, police did not show the pictures to anyone, including Kate and Gerry McCann in the days that followed Madeleine's abduction and insisted a case must be closed before they can release pictures of the suspects.

Yesterday, a friend of the Kate and Gerry McCann said it was "frankly outrageous" that neither e-fit was disclosed.

The couple's spokesman Clarence Mitchell said the couple had no idea that the images existed until they were released yesterday in the case files made available by the Portuguese police.

"This material was never shown to Kate, Gerry, Jane Tanner or anyone else in the group," he said.

"Seeing it in the files is the first they have known about it. Again, one has to ask what the police were doing by not making this material available at the time."

The similar images of a young, white man with dark and deep set eyes was put together from sightings by British holidaymaker Derek Flack and British expat Lance Purser.

Mr Flack saw a man acting suspiciously around the McCann's holiday apartment just before Madeleine went missing.

Mr Purser said he had seen a similar man in the weeks running up to her disappearance.

But neither e-fit was released and the only image Portuguese police circulated was a picture described as nothing more than an "egg with hair".

They said they could not release any images because of secrecy laws and the fear of prejudicing any further investigation.

But a friend of the McCanns said: "It is frankly outrageous that information relating to potential suspects was not made available as a matter of extreme urgency once it was clear what had happened.

"The early stages of this were crucial and the police of all people should know that. Seeing these images has come as a shock to everyone concerned."

The e-fits emerged as the public prosecutor overseeing the case heavily criticised the police, describing their actions as an "enormous margin of error".

In the 58-page report, prosecutors Jose de Magalhaes and Joao Melchior Gomes said: "The investigators are well aware that their work is not exempt from imperfections.

"They worked with an enormous margin of error and they achieved very little in terms of conclusive results."

They went on to say that the disappearance of Madeleine was not a plot from a book, but a serious crime without a satisfactory ending.

"This is not, unfortunately, a police story, a crime fit for the investigative mind of a Sherlock Holmes or a Hercule Poirot, guided by the illusion that the forces of law and justice always restore order."

Mr Flack, a freelance engineer designer from Ilford in Essex, has a holiday home in Praia da Luz, near the McCann's family's apartment at the Ocean Club resort.

On either May 2 or 3 last year – the day Madeleine disappeared – he saw a man standing near a dirty white van, staring intently at the couple's ground floor veranda.

He said he noticed that the man – aged between 25 and 35, tanned, medium height, with thick dark hair and fringe - was behaving oddly.

"He then realised the man was staring fixedly at the area in question, very focused on what he was doing, and did not notice Flack's presence," the transcript of his interview said.

When Mr Flack heard about Madeleine's disappearance, he immediately linked the two and contacted the police.

"He said he did not remember seeing the man there before, or anywhere else in Luz, since Madeleine's disappearance."

Mr Purser, 65, made a formal statement to police on the same day as Mr Flack, giving details about a suspicious man loitering around the town on his own.

The property manager said he had seen a thin white man, aged around 35, with dark straight collar length hair, whose skin had been aged by the skin.

The hunt for Madeleine was the biggest ever carried out Portuguese police but the public prosecutor said very little had been achieved.

"No element of proof whatsoever was found which allows us to form any lucid, sensible, serious and honest conclusion about the circumstances (of Madeleine's disappearance)."

Mr Magalhaes defended the McCanns' decision to leave their children alone in the apartment, saying they had not considered their children to be in any danger.

The prosecutor said all the theories – including the possibility that the couple had accidentally killed their daughter and disposed of her body – had come to nothing.

"While it is a fact that Madeleine disappeared from the Ocean Club apartment, the circumstances and manner of how this happened is not known."